A microscopic protrusion that is present on a top surface of a support base (hereinafter, such a protrusion will be referred to as a “protruding portion”) and a foreign object such as a particle or the like attached to the top surface of the support base (hereinafter, such a foreign object will be referred to as “contamination element”) may undesirably deteriorate the characteristics of a thin film or an element formed on the support base. For example, in the case where thin film transistors, interconnect lines and insulating layers are to be formed on a support base, such microscopic protruding portions or contamination elements on the top surface of the support base may cause defects to the thin film transistors, disconnect or shortcircuit the interconnect lines, or cause leakage in the insulating layers.
Patent Document No. 1 discloses a microscopic protrusion polishing device that puts a polishing tape into contact with a microscopic protrusion on a flat plate to polish the flat plate.